//交错字符串（medium）: https://leetcode.cn/problems/interleaving-string/description/
class Solution
{
public:
	bool isInterleave(string s1, string s2, string s3)
	{
		int m = s1.size(), n = s2.size();
		if (m + n != s3.size())
		{
			return false;
		}
		s1 = " " + s1;
		s2 = " " + s2;
		s3 = " " + s3;

		vector<vector<bool>> dp(m + 1, vector<bool>(n + 1));
		dp[0][0] = true;
		for (int j = 1; j <= n; j++) // 初始化第⼀⾏
		{
			if (s2[j] == s3[j])  dp[0][j] = true;
			else break;
		}
			
		for (int i = 1; i <= m; i++) // 初始化第⼀列
		{
			if (s1[i] == s3[i]) dp[i][0] = true;
			else break;
		}
	
		for (int i = 1; i <= m; i++)
		{
			for (int j = 1; j <= n; j++)
			{
				dp[i][j] = (s1[i] == s3[i + j] && dp[i - 1][j])
					    || (s2[j] == s3[i + j] && dp[i][j - 1]);
			}
		}
			
		return dp[m][n];
	}
};

//两个字符串的最⼩ ASCII 删除和（medium) : https://leetcode.cn/problems/minimum-ascii-delete-sum-for-two-strings/
class Solution
{
public:
	int minimumDeleteSum(string s1, string s2)
	{
		int m = s1.size(), n = s2.size();
		vector<vector<int>> dp(m + 1, vector<int>(n + 1));

		for (int i = 1; i <= m; i++)
		{
			for (int j = 1; j <= n; j++)
			{
				dp[i][j] = max(dp[i][j - 1], dp[i - 1][j]);
				if (s1[i - 1] == s2[j - 1])
				{
					dp[i][j] = max(dp[i][j], dp[i - 1][j - 1] + s1[i - 1]);
				}
			}
		}
			

		int sum = 0; // 统计元素和

		for (auto s : s1)
		{
			sum += s;
		}
		for (auto s : s2)
		{
			sum += s;
		}
		return sum - dp[m][n] - dp[m][n];
	}
};